1. Field of the Invention
The present invention relates generally to the field of wireless data communications and more particularly to reliable unidirectional data communications for use in a wireless optical network.
2. Description of Prior Art
Proliferation of the Internet has made it possible for users to access vast amounts of data almost effortlessly. For example, with only a few mouse clicks users may inundate themselves with data such as; commercial data, scientific data, educational data, financial data, and data on general areas of interest such as sports and hobbies. Ease of access to networked data has helped fuel demand for even more types of data. Accompanying users' demand for data is a desire to have data sorted based on user preferences before the data is viewed or utilized. Failure to deliver data to users in a sorted manner wastes the users' time, leads to network congestion because of repeated requests for new data, and wastes processing and storage resources if large amounts of data must be processed to present a user with relevant information.
Problems associated with unfiltered data are especially challenging when users wish to take advantage of information while remaining mobile. These users are increasingly relying on wireless devices such as personal digital assistants (PDAs), handheld computers and web enabled cell phones for processing information when on the go. One example would be a wireless device used to store personal contact information, calendars, email, business information, and financial information. While wireless devices have some processing capabilities, they are very limited when compared to desktop computing devices. Since wireless devices normally run on batteries, efforts must be made to reduce power consumption. Typically, slow speed processors and reduced memory sizes are employed to reduce power consumption. In addition, reducing the use of, or eliminating, power hungry add-on components such as radio frequency transceivers (e.g. cellular and wireless Ethernet), modems, global positioning system (GPS) receivers, and the like help to extend the life of batteries in wireless devices.
Context sensitive computing may be employed to address some of the shortcomings associated with providing unfiltered data to wireless devices. More specifically, context sensitive computing attempts to send users only data that is relevant to their needs. Context as used herein is comprised of two parts. The first part is environmental context and it describes the physical location of a user, e.g. an airport, a car, or a store. The second part is referred to personal context and it is associated with a user's personal preferences, e.g. a particular colored shirt, a favorite author, etc. In principle, context sensitive computing makes it possible to provide users of wireless devices having limited processing capabilities with relevant information.
To aid in the understanding of how contextual computing can aid users of wireless devices by providing them with relevant information, an example will be presented. In this example a consumer wants to make a purchase at a shopping mall. In addition, the consumer wants to have relevant information, such as the latest sale price and industry reviews for a desired product, and the consumer wants to know which merchant carries a particular style or colored item. The consumer has two primary options for using data to facilitate selection of a product and a possible purchase. For example, the consumer may first review data in their home or at a library and make notes or print copies of the materials to then take shopping with them. The disadvantage with this approach is that the consumer may be using stale data when attempting to make the purchase at the merchant's location. Alternatively, a consumer trying to avoid using stale data in facilitating a purchase may attempt to ask various merchants for the latest pricing and selection options of the desired product. This later approach has a disadvantage in that it does not use the consumer's time efficiently.
In the example above, the consumer would be better served if they employed wireless computing devices to ensure that the latest data is presented to them in the most efficient manner. In order to present a consumer with relevant information, the wireless device should be able to determine the environmental context that the consumer operating in the example. Where environmental context refers to the physical environment in which the consumer is operating, here a mall or a particular store within a mall. In addition, the wireless device should be able to sort available information so that a consumer is only presented with information that is relevant only to their interests.
Prior art techniques for determining environmental context rely on the wireless device for processing information to determine position; or they use the infrastructure (i.e. ground based transmitters) to process information received from a wireless device to establish its location. When the wireless device processes data to establish position, global positioning receivers (GPS) receivers are normally used. Some of the disadvantages associated with GPS receivers are that they require additional power and do not work well indoors. When the network infrastructure attempts to determine position, radio-frequency (RF) ranging techniques are used. RF ranging techniques normally employ beacons that transmit data to and receive data from wireless device. Some of the disadvantages associated with RF beaconing techniques are that their locational accuracy is not very good and the wireless device consumes excessive power when transmitting beacon signals or when processing received beacon signals.
Prior art techniques for communicating data to wireless devices also have shortcomings. RF signals are the primary means for transmitting data to wireless devices. Cellular, wireless Ethernet, BLUETOOTH™ (short-range communications of data and voice), and microwave are some of the most common prior art methods or communicating data to wireless devices. These forms of communication also consume large amounts of power.
It is thus an object of the present invention to eliminate problems associated with unidirectional communications.
It is a further object of the invention to reliably transmit infrared unidirectional signals to wireless handheld devices having limited processing capabilities.
It is yet a further object of the invention to employ easily parsed data structures when communicating to a wireless handheld device having limited processing ability.
It is still a further object of the invention to allow a handheld device to accept easily parsed reliable unidirectional communication signals without needing special receiving or processing hardware.